Method and apparatus for SL relay discovery in wireless communication system

A method of a user equipment (UE) in a wireless communication system, the method comprising:

• identifying a first resource pool for a sidelink (SL) relay discovery operation and a second resource pool for other SL transmission and reception operations, wherein the first resource pool comprises third and fourth resource pools;
• determining whether a signal transmission or reception is for the SL relay discovery operation or for the other SL transmission and reception operations;
• selecting the first resource pool for the signal transmission or reception based on a determination that the signal transmission or reception is for the SL relay discovery operation;
• selecting the second resource pool for the signal transmission or reception based on a determination that the signal transmission or reception is for the other SL transmission and reception operations;
• receiving a SL relay discovery solicitation message from a remote UE;
• identifying, based on the SL relay discovery solicitation message received by the UE, (i) a requested relay service code (RSC) or SL relay UE identifier (ID) of the remote UE and (ii) whether an indication of a type of a SL relay operation that the remote is interested in is present in the SL relay discovery solicitation message;
• determining, based on no indication of the type of the SL relay operation that the remote UE is interested in being present in the SL relay discovery solicitation message, the type of the SL relay operation for the remote UE corresponding the requested RSC or SL relay UE ID of the remote UE that is supported by the UE;
• selecting, based on the determined type of a SL relay operation for the remote UE, the third or fourth resource pool, wherein the type of the SL relay operation is a layer 2 UE to network (L2 UE2NW) relay or a layer 2 UE to UE (L2 UE2UE) relay;
• and
• performing the signal transmission or reception using the selected one of the first and second resource pools.

A base station (BS) in a wireless communication system, the BS comprising:

• a processor configured to generate a first resource pool for a sidelink (SL) relay discovery operation and a second resource pool for other SL transmission and reception operations, wherein the first resource pool comprises third and fourth resource pools;
• and
• a transceiver operably coupled to the processor, the transceiver configured to transmit information including the first resource pool for the SL relay discovery operation and the second resource pool for the other SL transmission and reception operations,
• wherein:
• the first resource pool is selected for a signal transmission or reception for the SL relay discovery operation,
• the second resource pool is selected for the signal transmission or reception for the other SL transmission and reception operations,
• the third or fourth resource pool is selected based on a type of a SL relay operation that a remote user equipment (UE) is interested in,
• the type of a SL relay operation for the remote UE is determined (a) based on a SL relay discovery solicitation message transmitted by the remote UE that includes (i) a requested relay service code (RSC) or SL relay UE identifier (ID) of the remote UE and (ii) no an indication of a type of a SL relay operation that the remote UE is interested in is present in the SL relay discovery solicitation message and (b) as corresponding the requested RSC or SL relay UE ID of the remote UE that is supported by a UE that received the SL relay discovery solicitation message, and
• the type of the SL relay operation is a layer 2 UE to network (L2 UE2NW) relay or a layer 2 UE to UE (L2 UE2UE) relay.